Electric coupling for the operation of x-ray tubes or other thermionic tubes



' y 1958 G. B. DAVIDSEN 2,833,934

ELECTRIC COUPLIN OR THE OPERATION OF X-RAY TUBES 0R 0 R THERMIQNIC TUBESTHE Filed June 30,

United States Patent f) ELECTRIC COUPLING FOR THE OPERATION OF Theinvention relates to an-electric coupling for the operation of X-raytubes or other thermionic tubes having an incandescent cathode and ananode, and two transformers the secondary windings of which provide thetube with high tension, at least one of the said transformers having awinding for supplying filament current to the incandescent cathode ofthe tube, the primary windings of the said transformers having a commonpoint, while the outer terminals of the said windings lying at thegreatest distance of the common point are connected to a regulatingtransformer, and of the kind having regulating means for the hightension and filament current of the tube.

Electric couplings of the aforesaid kind are known, but the regulatingmeans which are inserted in the coupling are frequently rathercomplicated and consequently less reliable in operation, addingsubstantially to the manufacturing cost of the installations in whichthey are used and the cost of operating these installations. Inaddition, the regulating means involve a substantial increase in weightand dimensions of the apparatus provided with the coupling, therebyreducing their applicability in portable installations and underunfavourable conditions of space.

The aforesaid drawbacks are eliminated in an electric coupling inaccordance with the invention thereby that the common point is connectedto a tapping point on the regulating transformer of the coupling, thedistances from the said tapping point to the points of connectionbetween the said outer terminal and the regulating transformer beingadjustable.

As a result, both the high tension and the filament current supplied tothe tube may be regulated within wide, predetermined limits, as avariation of the distance between the outer terminal of the firsttransformer having a winding for supplying filament current and thetapping point causes a variation in high tension and filament currentalike, whereas a variation in the distance between the outer terminal ofthe second transformer and the tapping point solely causes a variationin the high tension.

In one embodiment in accordance with the invention the tapping pointconsists of a sliding contact resting against a stripped part of thewinding of the regulating transformer, or against contact piecesconnected to the wires of the said winding.

As a result, the distance between the outer terminal of the firsttransformer and the tapping point may be increased or reduced, wherebythe high tension originating from the first transformer is increased orreduced, the high tension originating from the second transformer beingsimultaneously reduced or increased, respectively.

In another embodiment in accordance with the invention in which the oneouter terminal of one of the transformers is connected to a slidingcontact, the two sliding contacts are disposed each in a separate planeat right angles to the wires of the windings of the regulatingtransformer and may be adjusted independently of each other.

2,833,934 Patented May 6, 1958 As av result, the two sliding contactsmay pass .by each other along the windings of the regulatingtransformer, whereby the high tension originating from the secondtransformer may be used, for instance, to counteract the high tensionoriginating from the first transformer, andthe resulting high tensionmay therefore be reduced to a value lower than that corresponding to theadjustment ofthe sliding contact at the tapping point.

In a third embodiment in accordance with the invention the outerterminals are each connected with their separate sliding contact whichrests against a stripped part of the windingof the regulatingtransformer, or against contact pieces connected tothe wires of the saidwinding.

As a result, the. sliding contacts may be disposed in the same plane sothat the regulating transformer may be made of lower height, whereby afurther economy of space is obtained.

The invention will now be described in detail with reference to thedrawing, in which:

Figure 1 shows an embodiment of an electric coupling according to theinvention, connected to an X -ray tube;

Figure 2 is another embodiment of the said coupling;

Figure 3 is a perspective view of a coil having a stationary tap and apair of movable contacts arranged to pass each other;

Figure 4 is a view similar to Figure 3, but with the fixed tap soarranged that at least one contact is movable past said tap; and

Figure 5 is a view similar to Figures 3 and 4, but with the two contactsarranged to operate in a common plane.

An electric coupling in accodance with the invention consists of anX-ray tube 1 or another thermionic tube having an incandescent cathode 2and an anode 3 and two transformers 4 and 5 whose secondary windingssupply high tension to the tube 1, at least one of the said transformers(4) having a winding 6 for supplying filament current to theincandescent cathode 2. The primary windings of the transformers 4, 5are connected with each other at a common point 7, Whereas the outerterminals 9 and 10 of the said windings which are at the greatestdistance from the common point 7 are connected to a regulatingtransformer 8 which is connected to power lines at terminals 11 and 12.

In accordance with the invention the common point 7 is connected to atapping point 13 on the regulating transformer 8 of the coupling, andthe distances from the said tapping point 13 to the connecting points14, 15 of the outer terminals 9, 10 are adjustable.

In the embodiment of an electric coupling according to the invention asdisclosed in Figure 1 the tapping point 13 is constituted by a slidingcontact 13 resting against a stripped part of the Winding of thetransformer 8, or against contact pieces connected to some of the wiresof the said windings. The one outer terminal 14 may in known manner beconnected to a sliding contact of similar kind as that constituting thetapping point 13, and in accordance with the invention the two slidingcontacts 13 and 14 are then mounted in different planes at right anglesto the wires of the windings of the regulating transformer 8 and areadjustable independently of each other.

In the embodiment of an electric coupling according to the invention asshown in Figure 2 the outer terminals 9, 10 are each connected to theirseparate sliding contact which rests against a stripped part of thewindings of the regulating transformer 8, or against contact piecesconnected with some of the wires of the said windings. In order tosimplify the coupling the tapping point 13 may in this embodiment bemade as a permanent connection between the common point 7 and theregulating transformer 8, but alternatively it may also be proaesaosavvided with a sliding contact of the same kind as that described abovewith reference to Figure 1.

What I claim and desire to secure by Letters Patent is:

1. A regulating apparatus for thermionic tubes having an incandescentcathode and an anode, a pair of transformers for energizing the tube, atleast one of said transformers having a winding for supplying filamentcurrent to said incandescent cathode, the primary windings of saidtransformers having a common terminal as well as a pair of exteriorterminals, and a voltage regulating transformer connected to said commonterminal and having a pair of contacts connected to said exteriorterminals of said primary winding and having sliding contact toward andfrom each other over a stripped part of said regulating transformerwhereby the said primary windings as occasion requires may counteracteach other upon operation of said regulating transformer.

2. A regulating apparatus as claimed in claim 1 in which one of theexterior terminals of one of said primary windings is connected to asliding contact resting V in said common terminal is connected to astationary tap on the winding of the regulating transformer,characterized in that said stationary tap is situated at a distance fromboth of the ends of the said regulating transformer winding in such away that at least one of the sliding contacts is movable past the tap.

References Cited in the file of this patent UNITED STATES PATENTS1,600,316 Campbell Sept. 21, 1926 1,965,249 Morrison July 3, 19342,140,299 Pieper Dec. 13, 1938 Notice of Adverse Decision inInterference In Interference No. 90,07 6 involving Patent No. 2,833,934,G. B. Davidsen, Electric coupling for the operation of X-ray tubes orother thermionic tubes, final judgment adverse to the patentee wasrendered Oct. 18, 1961, as to claims 1 and 2.

[Ofiicz'al Gazette, April 1?, 1.962.]

